Inhibitory effect of TNP-470, a new anti-angiogenic agent, on the estrogen induced rat pituitary tumors.

An angiogenic inhibitor, TNP-470, is an analogue of fumagillin. This study reports the effects of TNP-470 and bromocriptine on the normal pituitary glands and estrogen-induced rat pituitary tumors. TNP-470 inhibited the increase of normal pituitary weight and the tumorigenesis induced by estrogen. The decreased labelling index in the pituitary cells, showed that TNP-470 may suppress the activity of cell proliferation as the result of anti-angiogenesis. Combination treatment with TNP-470 and bromocriptine was much more effective than TNP alone. These results suggest that TNP-470 is a potentially beneficial drug for pituitary tumors.